摘要
经470~520℃双级固溶处理的国产Al-Zn-Mg-Cu (7A85)合金分别在250、300、350、400和450℃施行厚度减缩量为80%的轧制变形后,立即经520℃、30 min完成再结晶退火处理。采用基于电子背散射衍射和五参数分析的晶界界面匹配表征方法对上述试样进行测试和分析发现,轧制温度对后续再结晶退火{111}/{111}近奇异晶界的形成有显著影响,表现为{111}/{111}近奇异晶界比例随轧制温度的升高呈现先上升、然后下降至一定值并保持基本恒定的变化规律;经300℃轧制及后续再结晶退火,{111}/{111}近奇异晶界比例达到极大值5.0%,是奇异晶界(共格孪晶界)比例的近10倍。对试样显微组织进行观察和分析表明,经300℃轧制,样品中形成特定变形亚结构,并且具备一定形变储能,在后续再结晶退火过程中,其组织演化以连续再结晶为主,有利于{111}/{111}近奇异晶界的形成。相反,经350℃及以上温度轧制,试样发生了不连续动态再结晶,不利于后续退火{111}/{111}近奇异晶界的形成;经250℃轧制,试样内存在较高储能,在后续退火过程中发生了不连续再结晶,也不利于{111}/{111}近奇异晶界的形成。离线原位表面侵蚀实验和高分辨透射电子显微镜观察表明,{111}/{111}近奇异晶界的腐蚀抗力显著高于一般晶界,此类晶界具有旋错结构特征,其结构有序度显著高于一般晶界。
Recent development in grain boundary design and control indicates that manipulating the {111}/{111} near singular boundaries will be a promising pertinent to improve the performance against intergranular corrosion attacks for the high stacking fault energy face-centered cubic metals such as aluminum and its alloys.In the current study,five samples of a home-made Al-Zn-Mg-Cu super-high-strength aluminum alloy were rolled at temperatures of 250,300,350,400,and 450oC,followed by 30 min annealing at 520oC.A method of grain boundary interconnection characterization based on electron backscatter diffraction and five parameter analysis was utilized to assess the {111}/{111} near singular boundaries in the samples as processed.The preceding rolling temperature was discovered to have a significant impact on the formation of {111}/{111} near singular boundaries during the subsequent annealing at 520oC,that is,the fraction of {111}/{111} near singular boundaries out of the entire grain boundaries increases at first and then decreases as the preceding rolling temperature increases from 250oC to 450oC.In the five samples as processed,the one rolled at 300oC followed by annealing at 520oC has a peak content of {111}/{111} near singular boundaries and the fraction reaches 5.0%,which is 10 times higher compared to that of the singular boundaries or namely the coherent twin boundaries.Further investigations reveal that the sample rolled at 300oC possesses a specific deformation substructure as well as suitable stored energy,resulting in continuous recrystallization during the successive annealing.This type of behavior aids in the formation of {111}/{111} near singular boundaries.The samples rolled at or above 350oC,on the other hand,exhibit discontinuous dynamic recrystallization,which is detrimental to the development of {111}/{111} near singular boundaries during subsequent annealing.Compared to the sample rolled at 300oC,the sample rolled at 250oC has higher stored energy and it improves discontinuous recrystallization during
作者
王宗谱
王卫国
Gregory S Rohrer
陈松
洪丽华
林燕
冯小铮
任帅
周邦新
WANG Zongpu;WANG Weiguo;Rohrer Gregory S;CHEN Song;HONG Lihua;LIN Yan;FENG Xiaozheng;REN Shuai;ZHOU Bangxin(Institute of Grain Boundary Engineering,Fujian University of Technology,Fuzhou 350118,China;School of Materials Science and Technology,Fujian University of Technology,Fuzhou 350118,China;Department of Materials Science and Engineering,Carnegie Mellon University,Pittsburgh,PA15213-3890,USA;Institute of Materials,Shanghai University,Shanghai 200072,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第7期947-960,共14页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51971063
中央引导地方科技发展专项项目No.2019L3010。
关键词
AL-ZN-MG-CU合金
超高强铝合金
近奇异晶界
晶界界面匹配
晶界腐蚀
AI-Zn-Mg-Cu alloy
super-high strength aluminum alloy
near singular boundary
grain boundary inter-connection
intergranular corrosion
